The intramedullary fixation devices had been in existence since 1940. The Interlocking Nail is a cylindrical hollow rod connected with the sets of 2 or 3 screws on either ends. Since then, few minor modifications such as increase in the number of screws were introduced in the design/structure of the interlocking nail.
The interlocking screw provides the rotational stability at the fracture site and improves the Nail-Bone Construct stability. However no improvement in fracture biology is seen. Further, the prior art does not discuss about extra compression at the fracture provided by interlocking nail.
Indian Patent Application 1088/MUMNP/2005 provides an intramedullary nail for the fixation of fractures of the proximal femur, with a femur neck screw, installable with a proximal femur nail, into the intramedullary area, by a diagonal bore, running to the longitudinal axis of the femur nail, from the side of the femur nail, and a locking element with at least one branch parallel to the axis of the femur neck screw. The connection between the locking element and a groove in the bore of the femur nail forms a twisting lock of the femur neck screw and allows for the axial movement of the femur neck screw in the bore of the femur nail.
Indian Patent Application No. 3544/DELNP/2005 provides an intramedullary nail that has a distal end suitable for insertion in the medullary space. The intramedullary nail has several cross holes with a hole axis, each of which defines a virtual drill cylinder with a cylinder axis corresponding to the hole axis of the defining cross hole. The drill cylinders of at least two cross holes penetrate each other. The cylinder axis of the two mutually penetrating drill cylinders do not have any common intersection point on the longitudinal axis, resulting in improved mechanical strength without any need for the size of the cross section of the medullary nail to be increased.
Indian Patent Application No. 3986/DELNP/2012 provides systems, devices and methods for limiting compression of a fracture imposed by a lag screw of a fixation system that includes a fixation device, a lag screw and a compression screw. The disclosed devices, systems and methods prevent over-compression of a fracture by a lag screw caused by over rotation of the compression screw.
Indian Patent Application 3656/DELNP/2006 provides an intramedullary nail designed in particular for the tibia and has three distinct locking sections with at least one through-hole each for receiving locking screws. The said three locking sections are separated from each other by two distinct intermediate sections having less through-holes (8) per length unit than each of the locking sections (5, 6, 7).
The intra-medullary nails mentioned above for fixation of fractures are inserted in the medullary space. However, none of the prior art discusses about the improved and enhanced healing of the bone irrespective of the weight bearing cycle. The present invention relates to increasing bone healing due to the continuous compression caused by the Endo-Compression Screw that is inbuilt in the interlocking system. Additionally, none of the prior arts suggest the use of auto graft (i.e cancellous bone graft) in the interlocking nail obtained from medullary cavity of bone which is being operated.